Jet Pump pressure loss and pump recycling

[JESS28]

Hi there, I am new to Jet pumps. I have a Myers 1/3 hp H series jet pump for shallow wells. The pressure switch is set to 40/60. After enough water is used - the pump kicks in at 40 psi and builds to 60 psi and then shuts off. Pressure is then lost - pump clicks and pressure gauge fluctates up/down wildly until 40 psi and then the pump kicks in again and builds pressure. This process is repeated over and over. The only way to hold the pressure at 60 psi is to shut off the water coming up from the cistern as soon as the pump cuts out at 60 psi. The water can then be turned back on ...and if there isn't any water heard in the hose...the pressure holds until the next toilette flush etc. The shraeder valve is located on the pump itself rather than the tank and I believe the tank is galvanized with an air valve on the bottom 1/3 of the tank that determines the water level. The check valve has been replaced at the cistern and at pump. Water leaks from the shraeder valve when the valve is depressed. Any ideas would be very much appreciated. Jess28 :)

[nomind]

Hi Jess28,
- to recharge the tank, switch off the pump, and drain tank to the level of the input pipe. Now pump in air at the tank valve till the gauge reads 38 psi. Switch the pump on and all should now be normal. :cool:

Do it Right - Do it once.

[JESS28]

Thanks, I'll try precharging the tank. I tried this once but could not get air into the shraeder valve (I think it's shot) on the pump. Also I don't think we drained the tank down to the outlet pipe. Will have to replace the shraeder valve and try this again. I'll let you know what happens!

[nomind]

Hi Jess,-
- you don't put it in at the pump. There has to be a valve on the tank somewhere. That's a better place to charge it :cool:

Do it Right -Do it once.

[JESS28]

Well, that's what I thought, but I can't find one anywhere - just on the pump itself.